1. Field of the Invention
The present invention relates to a system with read protecting function and a method for protecting a record medium, and more particularly to a record medium having a control data zone and a data zone with encoded data therein, when the record medium is loaded into an optical storage device, the optical storage device will read and identify the control code; then the optical storage device will decode the encoded data and output the decoded data if the control code is identifiable; or the optical storage device will directly output the encoded data if the control code is not identifiable.
2. Description of the Related Art
In general, audio and video files can be downloaded from a server and played in a DVD or CD player by means of a simple security check according to a prior art. However, the security check may be skipped by users, and thus DVD or CD publishers cannot request users to pay for the downloaded files and thus the unauthorized use of DVD or CD media becomes more and more.
At present, there are systems or solutions that can solve the problem of protecting DVD or CD from unauthorized copying. For example, U.S. Pat. No. 5,991,403 issued to Aucsmith, et al disclosed a method for encoding MPEG compatible video data for subsequent compression that comprises detecting a plurality of frames of video data organized as a GOP, generating an encryption key for the GOP, and encrypting the video data using GOP-synchronized substitution, transposition, and rotation transformations that are parameterized by offsets derived from the generated encryption key.
U.S. Pat. No. 5,915,018 issued to Aucsmith, et al disclosed a cryptographic system and method for secure distribution and management of cryptographic keys for use in a DVD copy protection scheme. A DVD disc having compressed, encrypted content written on a first portion of the disc, and the content encryption key, itself encrypted with a second key and written out of band on a second portion of the disc is used to provide content, key, and control information to a DVD player.
U.S. Pat. No. 5,991,403 is used for coding MPEG compatible video data for subsequent compression, and U.S. Pat. No. 5,915,018 is a cryptographic system and method for secure distribution and management of cryptographic keys for use in a DVD copy protection scheme. However, these patented technologies all used the encryption key or cryptographic key to manage the data encrypting or decrypting of the CD or DVD. But the structure of the encryption key or cryptographic key was relative complex, furthermore, this method needs to pay more royalty fee to the publishers, filmmakers or computer companies, so as to increased the cost of the CDs or DVDs, therefore, the sale price of the CDs or DVDs could not be reduced.